poppler-ts

poppler-ts

A native Node.js binding for the Poppler PDF library, providing high-performance access to PDF documents through TypeScript/JavaScript.

Features

• 📄 Load PDF documents from file paths or buffers
• 📊 Extract comprehensive document metadata
• 🔓 Handle password-protected PDFs with unlock functionality
• 📖 Extract plain text from pages
• 🧱 Get structured text boxes with precise coordinates
• 📋 Export page content to detailed JSON with word-level positioning
• 🖼️ Render pages to high-quality images (ARGB32 format)
• 📐 Get accurate page dimensions, rotation, and properties
• 🔄 Support for page rotation and duration (for presentations)
• ⚡ High-performance native C++ implementation
• 🔧 Full TypeScript support with type definitions

Prerequisites

System Dependencies

You need Poppler development libraries installed on your system:

Ubuntu/Debian

sudo apt-get update
sudo apt-get install libpoppler-cpp-dev build-essential

macOS (with Homebrew)

brew install poppler

Windows (with vcpkg)

vcpkg install poppler[cpp]:x64-windows

Node.js Requirements

• Node.js >= 14.0.0
• Python 3.x (for node-gyp compilation)
• C++ compiler toolchain (GCC/Clang on Unix, MSVC on Windows)

Installation

npm install poppler-ts

Automatic Build Process

When you install the package, it will automatically attempt to build the native addon:

• System Check: The installer checks for Poppler development libraries
• Native Build: Compiles the C++ binding using node-gyp
• Verification: Confirms the binary was created successfully

Manual Build (if automatic build fails)

If the automatic build fails, you can build manually after installing system dependencies:

# Install system dependencies first, then:
npm run build:native

Development Setup

If you're developing or need the full source:

• Clone the repository:

git clone https://github.com/maifeeulasad/poppler-ts.git
cd poppler-ts

• Install dependencies:

pnpm install

• Build the native addon and TypeScript:

pnpm build

Usage

Basic Usage

import { Document } from 'poppler-ts';
import * as fs from 'fs';

// Load a PDF document
const doc = Document.loadFromFile('./document.pdf');

// Or load from buffer
const buffer = fs.readFileSync('./document.pdf');
const doc2 = Document.loadFromBuffer(buffer);

// Get basic document info
console.log('Pages:', doc.getPageCount());
console.log('Is locked:', doc.isLocked());
console.log('Metadata:', doc.getMetadata());

Working with Pages

// Get the first page
const page = doc.getPage(0);

// Get page properties
const size = page.getSize();
console.log(`Page size: ${size.width}x${size.height} points`);

// Extract text
const text = page.getText();
console.log('Page text:', text);

// Get page rotation
const rotation = page.getRotation();
console.log(`Page rotation: ${rotation}°`);

Advanced Text Extraction

// Get text boxes with coordinates
const textBoxes = page.getTextBoxes();
console.log(`Found ${textBoxes.length} text boxes`);

textBoxes.forEach((box, index) => {
  console.log(`Box ${index + 1}: "${box.text}"`);
  console.log(`  Position: (${box.bbox.x}, ${box.bbox.y})`);
  console.log(`  Size: ${box.bbox.width}x${box.bbox.height}`);
});

JSON Export with Detailed Positioning

// Export page content to structured JSON
const pageJSON = page.exportToJSON();

console.log(`Page dimensions: ${pageJSON.page.width}x${pageJSON.page.height}`);
console.log(`Found ${pageJSON.lines.length} text lines`);

pageJSON.lines.forEach((line, index) => {
  console.log(`Line ${index + 1}: "${line.text}"`);
  console.log(`  Words: ${line.words.length}`);

  line.words.forEach((word, wordIndex) => {
    console.log(`    Word ${wordIndex + 1}: "${word.text}" at (${word.bbox.x}, ${word.bbox.y})`);
  });
});

Image Rendering

// Render page to image
const image = page.renderToImage({
  dpi: 150,
  rotation: 0
});

console.log(`Rendered image: ${image.width}x${image.height}`);
console.log(`Format: ${image.format}`);
console.log(`Data size: ${image.data.length} bytes`);

// Save as PNG (requires additional image processing library)
fs.writeFileSync('page.png', image.data);

Handling Password-Protected PDFs

// Check if document is locked
if (doc.isLocked()) {
  // Try to unlock with password
  const unlocked = doc.unlock('password123');
  if (!unlocked) {
    console.error('Failed to unlock document');
    return;
  }
}

// Now you can access the document content
const page = doc.getPage(0);
const text = page.getText();

API Reference

Document Class

Static Methods

• Document.loadFromFile(filepath: string, password?: string): Document
  • Load PDF from file path
  • Optional password for encrypted PDFs
• Document.loadFromBuffer(buffer: Buffer, password?: string): Document
  • Load PDF from memory buffer
  • Optional password for encrypted PDFs

Instance Methods

• getPageCount(): number
  • Returns the total number of pages
• getPage(pageIndex: number): Page
  • Returns a Page object for the specified index (0-based)
• getMetadata(): DocumentMetadata
  • Returns document metadata as key-value pairs
• isLocked(): boolean
  • Returns true if the document is password-protected
• unlock(password: string): boolean
  • Attempts to unlock the document with the provided password

Page Class

Instance Methods

• getSize(): PageSize
  • Returns page dimensions and position
• getText(): string
  • Extracts all text content from the page
• getTextBoxes(): TextBox[]
  • Returns text boxes with precise coordinates
• exportToJSON(): PageJSON
  • Exports page content with detailed positioning information
• renderToImage(options?: RenderOptions): RenderedImage
  • Renders the page to an image buffer
• getRotation(): number
  • Returns page rotation in degrees (0, 90, 180, 270)
• getDuration(): number
  • Returns page duration for presentation PDFs

Type Definitions

interface PageSize {
  width: number;   // Page width in points
  height: number;  // Page height in points
  x: number;       // X offset (usually 0)
  y: number;       // Y offset (usually 0)
}

interface RenderOptions {
  dpi?: number;     // Resolution (default: 72)
  rotation?: number; // Additional rotation in degrees (default: 0)
}

interface RenderedImage {
  data: Buffer;        // Raw image data in ARGB32 format
  width: number;       // Image width in pixels
  height: number;      // Image height in pixels
  bytesPerRow: number; // Bytes per row
  format: string;      // Always "ARGB32"
}

interface TextBox {
  text: string;
  bbox: {
    x: number;
    y: number;
    width: number;
    height: number;
  };
}

interface Word {
  text: string;
  bbox: {
    x: number;
    y: number;
    width: number;
    height: number;
  };
}

interface Line {
  text: string;
  bbox: {
    x: number;
    y: number;
    width: number;
    height: number;
  };
  words: Word[];
}

interface PageJSON {
  page: {
    width: number;
    height: number;
    rotation: number;
  };
  lines: Line[];
}

interface DocumentMetadata {
  [key: string]: string; // Key-value pairs of metadata
}

Build Scripts

• pnpm build - Build both native addon and TypeScript compilation
• pnpm build:native - Build only the native C++ addon using node-gyp
• pnpm build:ts - Compile only TypeScript files
• pnpm clean - Clean build artifacts and native addon
• pnpm test - Run the test suite with a sample PDF
• pnpm example - Run the example demonstrating advanced features
• pnpm lint - Check code style with ESLint
• pnpm lint:fix - Automatically fix linting issues

Testing

The project includes comprehensive tests that demonstrate all functionality:

• Basic document operations: Loading, page count, metadata
• Page operations: Size, rotation, text extraction
• Advanced features: Text boxes, JSON export, image rendering
• Password protection: Document locking/unlocking

To run tests:

# Place a test PDF file at ./test.pdf
pnpm test

For advanced feature examples:

pnpm example

Project Structure

├── src/
│   ├── cpp/                 # C++ native binding source
│   │   ├── poppler_binding.cpp  # Main binding file
│   │   ├── document.h       # Document class header
│   │   ├── document.cpp     # Document class implementation
│   │   ├── page.h           # Page class header
│   │   └── page.cpp         # Page class implementation
│   ├── types/               # TypeScript type definitions
│   │   └── index.ts         # Complete API type definitions
│   ├── index.ts             # Main TypeScript entry point
│   ├── test.ts              # Comprehensive test suite
│   └── example.ts           # Advanced features demonstration
├── dist/                    # Compiled JavaScript output
├── build/                   # Native addon build artifacts
│   └── Release/
│       └── poppler_binding.node
├── .github/workflows/       # CI/CD workflows
│   ├── lint.yml            # Linting on push/PR
│   └── publish2npm.yaml    # NPM publishing on release
├── binding.gyp             # node-gyp build configuration
├── eslint.config.ts        # ESLint configuration
├── package.json            # Project configuration
├── tsconfig.json           # TypeScript configuration
└── README.md

CI/CD

The project includes GitHub Actions workflows for:

• Linting: Runs on every push and pull request to ensure code quality
• Publishing: Automatically publishes to NPM when a release is created

Both workflows include the necessary system dependencies for building the native addon.

Installation Issues

If the automatic build fails during npm install:

• Install system dependencies for your platform (see Prerequisites section above)
• Manual build: Run npm run build:native after installing dependencies
• Verify installation: Check that build/Release/poppler_binding.node exists
• Clear cache: Try npm cache clean --force and reinstall

Troubleshooting

Build Issues

• Missing Poppler libraries:

  # Ubuntu/Debian
  sudo apt-get update
  sudo apt-get install libpoppler-cpp-dev build-essential
  
  # macOS
  brew install poppler
  
  # Windows
  vcpkg install poppler[cpp]:x64-windows
  

• node-gyp compilation errors:

  • Ensure Python 3.x is installed and in PATH
  • On Windows, install Visual Studio Build Tools
  • Clear node-gyp cache: npm explore node-gyp -- npm run clean

• macOS path issues:

  export PKG_CONFIG_PATH="/opt/homebrew/lib/pkgconfig:$PKG_CONFIG_PATH"
  pnpm run build:native
  

Runtime Issues

• Module not found: Ensure native addon was built:

  ls build/Release/poppler_binding.node
  

• PDF loading errors: Check file permissions and PDF validity

• Memory issues: Large PDFs may require more memory allocation

• Text extraction issues: Some PDFs may have complex layouts

Performance Notes

• Native C++ implementation provides excellent performance
• Image rendering at high DPI may consume significant memory
• Text extraction is optimized for speed
• JSON export includes detailed positioning for advanced use cases

Contributing

• Fork the repository
• Create a feature branch
• Make your changes with tests
• Ensure linting passes: pnpm lint
• Submit a pull request

License

MIT License - see LICENSE file for details.

Dependencies

Runtime

• node-addon-api - Node.js C++ addon API
• Poppler - PDF rendering library

Development

• TypeScript for type safety
• ESLint for code quality
• node-gyp for native compilation
• ts-node for running TypeScript directly

Acknowledgments

Built with the excellent Poppler PDF library and Node.js addon API.